1. Field of the Invention
The present invention relates to closure applicators. Specifically, the present invention relates to closure applicators for container blanks.
2. Description of the Related Art
Containers such as gable top cartons and the ubiquitous TETRA BRIK.RTM. parallelepiped package, have always been popular as containers for liquid foods such as milk, orange juice and the like. Recently, the use of closures, or fitments, to access the contents have become very appealing to consumers due the resealability and tamper-proof features.
Numerous applicators have been invented that apply a closure/fitment to an erected carton or a completely formed, filled, and sealed carton. For example, a very efficient process for applying a fitment through a pre-cut hole in an erected carton is described in U.S. pat. No. 5,819,504. Another efficient process is described in U.S. pat. No. 5,829,228 which hot melts a fitment to an erected carton. Other applicators apply the fitment to a filled and sealed carton through use of hot melt. Although the packaging industry has created numerous applicators for applying a fitment to an erected carton or sealed carton, the industry has failed to provide a process or apparatus for applying a closure/fitment to an unerected carton blank.
Other problems arise with providing a closure on a TETRA BRIK.RTM. package since the formation of the package is on a vertical form, fill and seal machine from a roll of packaging material which is sealed longitudinally to form a tube and traversely cut to produce an individual package which is folded into the parallelepiped shaped. The roll of packaging material is immersed in a hydrogen peroxide bath and conveyed through a series of winding rollers on the machine.
The main reason for the failure is that these containers are coated with a polymer material such as polyethylene. The interior and exterior surface of the container are coated thereby creating a potential for adhesion between overlying surfaces if heat (as used in hot melt application) or pressure (ultrasonic welding) is used to attach a closure to an unerected carton blank or a tube of packaging material.
The failure to resolve this problem restricts application of closures/fitments to the form, fill and seal machine through either integrated machinery or machine in-line with the packaging machine. Also, the use of integrated machinery causes problems with maintaining a sterile environment for aseptic packaging.